Problem: Simplify the following expression: ${4z-13+z+4}$
Rewrite the expression to group the ${z}$ terms and numeric terms: $ {4z + z} {-13 + 4}$ Combine the ${z}$ terms: $ {5z} {-13 + 4}$ Combine the numeric terms: $ {5z} {-9}$ The simplified expression is $5z-9$